1. Field of the Invention
The present invention relates to methods of and systems for lighting and, more particularly, but not by way of limitation, to a LED lighting system for buses, trains, and the like affording improved lighting and simplifying maintenance and replacement of light sources therein.
2. History of Related Art
Commercial transportation vehicles have been accommodating the needs of passengers for well over a century. Of the passenger safety and comfort considerations addressed in designs of commercial transportation vehicles is the lighting system therein. Contemporary commercial vehicles such as buses utilize commercially available lighting fixtures for the safety and convenience of the bus passengers. These fixtures often incorporate conventional light technology such as fluorescent bulbs which inherently have certain functional, liability and safety considerations. These considerations include the fact that the lamps are manufactured with an electrical terminal on each end and, when installed into the lighting system, the electrical sockets block the light from the lamp. This can create dark spots within the lighted environment. An additional aspect is the fact that fluorescent lamps are manufactured and available in discrete sizes. Not all areas to be lighted are of the same size or are particularly adapted to the discrete sizes for which the lamps are manufactured. This design limitation also leads to dark areas in applications where the lamp needed for the lighting system is between the available lamp sizes.
Other safety considerations must also be considered. Fluorescent lamps operate on high voltage, alternating current which creates “arcing” within the lamp as part of the light generating process. Fluorescent lamps that have reached “end of life” do not generate light in any section of the entire lamp length, which creates large dark areas in the application environment. This fact also leads to the requirement for regular maintenance which is both costly and time consuming. An additional safety issue is the fact that fluorescent lamps contain mercury, argon or neon gas, and phosphor; which requires special disposal practices to prevent environmental issues. Likewise, if the lamp is broken within a contained environment, such as a bus, there are passenger safety issues and contamination aspects that must be dealt with.
Finally, fluorescent lamps, as described above, experience diminished operational life due to the application environment and increased repetitive on/off power cycling. This cycling increases the occurrence of lamp replacement and the opportunity for harm to personnel and environment, which may require the need for increased personnel training.
The disadvantages of fluorescent lights can be overcome with the use of the innovated light source system known as light emitting diodes (LEDs). Lighting systems based on LEDs have advantages over traditional fluorescent lighting systems, including the fact that they do not contain dangerous gasses and the fact that their operational life is not diminished by repetitive on/off power cycling.
Additionally, it has been recognized that LED lighting systems can be constructed in select lengths and lighting effects. For example, LED lighting systems can be controlled to vary both color and brightness to create subtle lighting effects, such as sunrise, sunset, and mood lighting, and as well as appropriate ambient lighting for reading and the like. Because of these and other advantages, LED lighting systems are rapidly replacing traditional fluorescent lighting systems in a number of environments, including transportation, military, commercial, and home environments.
Some LED lighting systems include lighting devices that can generate light of variable color and intensity under processor control. Multiple lighting devices of a modular design can be incorporated into lighting systems to illuminate larger areas. A lighting module may include, for example, groups of LEDs, each of which generates light of a different color and whose intensity can be controlled.